Mobile communication has changed the way people communicate and mobile phones have been transformed from a luxury item to an essential part of every day life. The use of mobile phones today is generally dictated by social situations, rather than being hampered by location or technology. While voice connections fulfill the basic need to communicate, and mobile voice connections continue to filter even further into the fabric of every day life, the mobile Internet is the next step in the mobile communication revolution. The mobile Internet is poised to become a common source of everyday information, and easy, versatile mobile access to this data will be taken for granted.
The General Packet Radio Service (GPRS) and Enhanced Data rates for GSM (EDGE) technologies may be utilized for enhancing the data throughput of present second generation (2G) systems such as GSM. The GSM technology may support data rates of up to 14.4 kilobits per second (Kbps), while the GPRS technology, introduced in 2001, may support data rates of up to 115 Kbps by allowing up to 8 data time slots per time division multiple access (TDMA) frame. The GSM technology, by contrast, may allow one data time slot per TDMA frame. The EDGE technology, introduced in 2003, may support data rates of up to 384 Kbps. The EDGE technology may utilizes 8 phase shift keying (8-PSK) modulation for providing higher data rates than those that may be achieved by GPRS technology. The GPRS and EDGE technologies may be referred to as “2.5G” technologies.
Third generation (3G) cellular networks have been specifically designed to fulfill these future demands of the mobile Internet. As these services grow in popularity and usage, factors such as cost efficient optimization of network capacity and quality of service (QoS) will become even more essential to cellular operators than it is today. These factors may be achieved with careful network planning and operation, improvements in transmission methods, and advances in receiver techniques. To this end, carriers need technologies that will allow them to increase downlink throughput and, in turn, offer advanced QoS capabilities and speeds that rival those delivered by cable modem and/or DSL service providers. In this regard, networks based on wideband CDMA (WCDMA) technology may make the delivery of data to end users a more feasible option for today's wireless carriers.
The UMTS technology, introduced in 2003, with theoretical data rates as high as 2 Mbps, is an adaptation of the WCDMA 3G system by GSM. One reason for the high data rates that may be achieved by UMTS technology stems from the 5 MHz WCDMA channel bandwidths versus the 200 KHz GSM channel bandwidths.
High speed downlink packet access (HSDPA) and High speed uplink packet access (HSUPA) technology provide an Internet protocol (IP) based service, oriented for data communications, which adapts WCDMA to support data transfer rates on the order of 10 megabits per second (Mbits/s). Developed by the 3rd Generation Partnership Agreement (3GPP), the HSDPA and HSUPA technologies achieve higher data rates through a plurality of methods. For example, within HSDPA many transmission decisions may be made at the base station level, which is much closer to the user equipment as opposed to being made at a mobile switching center or office. These may include decisions about the scheduling of data to be transmitted, when data is to be retransmitted, and assessments about the quality of the transmission channel. These technologies may also utilize variable coding rates.
In 3GPP, these base stations may be referred to as “Node B's” and the wireless terminals may be referred to as user equipment (UE). In operation, each Node B communicates with a plurality of wireless UEs operating in its cell/sectors. A controller coupled to the Node B routes voice, video, data or multimedia communications between the UE and a packet data network that may include or couple to the Internet. Transmissions from base stations to wireless terminals are referred to as “forward link” or “downlink” transmissions while transmissions from wireless terminals to base stations are referred to as “reverse link” or “uplink” transmissions. The volume of data transmitted on the forward link typically exceeds the volume of data transmitted on the reverse link. Such is the case because data users typically issue commands to request data from data sources, e.g., web servers, and the web servers provide the data to the wireless terminals. The great number of wireless terminals communicating with a single Node B forces the need to divide the forward and reverse link transmission resources (depending on the specific wireless standards, the resources could be frequency band, time slot, orthogonal code, and transmit power) amongst the various wireless terminals.
In some instances, HSDPA and HSUPA may provide a two-fold or greater improvement in network capacity as well as data speeds up to five times (over 10 Mbit/s) higher than those in even the most advanced 3G networks. HSDPA may also shorten the roundtrip time between network and terminal, while reducing variances in downlink transmission delay. These performance advances may translate directly into improved network performance and higher subscriber satisfaction. Since HSDPA and HSUPA are an extension of the GSM family, it also builds directly on the economies of scale offered by the world's most popular mobile technology. Those improvements may directly translate into lower cost-per-bit, faster and more available services, and a network that is positioned to compete more effectively in the data-centric markets of the future.
The capacity, quality and cost/performance advantages of HSDPA and HSUPA yield measurable benefits for network operators, and, in turn, their subscribers. For operators, this backwards-compatible upgrade to current WCDMA networks is a logical and cost-efficient next step in network evolution. When deployed, HSDPA and HSUPA may co-exist on the same carrier as the current WCDMA Release 99 services, allowing operators to introduce greater capacity and higher data speeds into existing WCDMA networks. Operators may leverage this solution to support a considerably higher number of high data rate users on a single radio carrier.
HSUPA and HSDPA make true mass-market mobile IP multimedia possible and while at the same time reducing the cost-per-bit of service delivery, thus boosting both revenue and bottom-line network profits. For data-hungry mobile subscribers, the performance advantages of HSDPA/HSUPA may translate into shorter service response times, less delay and faster perceived connections. Users may also download/upload packet-data over HSDPA/HSUPA while conducting a simultaneous speech call.
However, implementing advanced wireless technologies such as WCDMA and/or HSDPA and HSUPA may still require overcoming some architectural hurdles because of the very high-speed, wide bandwidth data transfers possible. For example, unlike a desktop computer, the processors within the wireless terminal are assigned multiple processing duties. The processing of the data received to determine the need for retransmission takes place at the UE, these processing operations may be very sensitive to processing time. It is therefore important to devise methods that may lead to a minimum processing time for the determination of the need for a fast retransmission of lost packets without placing increasing demands on the processors and capacity of the UE. The addition of processing requirements within the wireless terminal requires new methods with which to balance data processing within the UE's while maintaining service.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.